Petroleum and petroleum-based products are widely used in various industrial processes, ranging from such uses as, for example only, fuels, waxes, and intermediates in the production of a number of products, such as polyethylenes and plastics. However, a problem with the use of petroleum and petroleum-based products is that their supply is dwindling, their price and supply is subject to fluctuation, and this is often affected by political and other factors that are outside of supply and demand matters.
On the other hand, products derived from plant and vegetable products, and animal products, are considered to be renewable products because plant and vegetable crops can be regularly cultivated, and animals can be raised in a similar manner. Because products derived from these sources can be regenerated, these products could also be considered to be “eco-friendly”.
This invention relates to a process for upgrading low-grade renewable oils such as vegetable oils and animal fats, into products that can cost-effectively replace non-renewable petroleum based products. The low-grade, or low value oils are derived from several sources including spent frying oil, rancid oils, and vegetable oils that have been lightly processed. Reprocessed or recycled oils that would otherwise be considered substandard may also be utilized in this process. The low value renewable oils are processed by partial hydrogenation into solid waxes that can be used in value added applications such as water resistant coatings for materials such as boxboard, wood composites, oriented strand board and hardboard siding applications; water-resistant additive to gypsum and related products; use in emulsions for water resistant coatings; use in printing inks to reduce mar and rubbing of the applied ink; use in various types of adhesives, for example, hot-melt adhesives and adhesives used in packaging applications; use as a plastics processing aid, such as a lubricant for the extrusion of polyvinyl carbonate plastic; use in candle manufacturing; and use in fire logs and fire starter products. Yet another application for the renewable waxes of the present invention involves their use as an additive for the modification of asphalt.
The major processes for the hydrogenation of oils involves a number of steps in order to “clean up” the final product, and these include steps of degumming, deodorizing and bleaching the processed oil.
U.S. Pat. No. 7,910,758 B2 (“the '758 patent”, the contents of which are incorporated by reference herein in their entirety), by several of these inventors and assigned to the same assignee as the present specification, describes many of the parameters involved in conventional hydrogenation processes. Generally, unsaturated triglycerides are refractory towards hydrogenation, and typically require high temperature, high pressure, prolonged hydrogenation time or combinations thereof in order to obtain satisfactory hydrogenation. Conventionally, unsaturated triglycerides are hydrogenated with hydrogen gas in the presence of at least 0.2 to 0.5% nickel hydrogenation catalyst, and sometimes a higher quantity of catalyst, at temperatures at or above 150 degrees C., and under pressures of from 60 psig to 100 psig or greater. Reaction times of at least 1 to 8 hours or longer are generally required, depending upon the degree of hydrogenation desired.
While advances have been made in catalyst chemistry, it has been difficult to accelerate the hydrogenation reaction itself. In the '758 patent, processes to accelerate the hydrogenation reaction, utilizing a high shear device, have been described. As will be described in the present specification, applicants utilize these processes for the preparation of partially hydrogenated products from what are considered to be “low-value”, yet renewable oil products, which can then be utilized in the production of other commercially valuable products, rather than being discarded.
Among the potential uses for these upgraded oils produced by embodiments of the present invention are uses as coatings of cellulosic products to render them water resistant, or such uses as in the production of fire logs.
U.S. Pat. App. Pub. No. 2005/0016062 A1 discloses a fire log made of recycled materials, and a method for manufacturing such a fire log. The fire log comprises a solid fuel block that is oversaturated with a vegetable oil. The fire log is wrapped in a wax-coated wrapper.
U.S. Pat. App. Pub. No. 2006/0021276 A1 discloses an environmentally friendly fire log made of recycled materials, and a method for manufacturing such a fire log. The fire log includes a combustible material, a plant oil and a wax that are blended to form the fire log The combustible material includes wood fibers, sawdust and/or wood flour, the plant oil is a modified tall oil pitch residue, and the wax a polyethylene wax.
U.S. Pat. No. 6,811,824 B2, to the same assignee as the present specification, discloses use of fully hydrogenated vegetable waxes to render cellulosic articles, such as cardboard, boxboard, linerboard, and the like water resistant. The applied coating is also capable of being removed by immersion of the treated products in a warm, alkaline, aqueous solution, such that the treated products no longer need to be disposed of in a landfill, but can, instead, be recycled WO 2009/013328 A1 and WO 2009/062925A1 describe an additive package for modification of asphalt properties that includes a wax component including vegetable waxes. The examples utilize either Fischer-Tropsch or polyethylene waxes, and a vegetable wax mentioned (carnauba) is a costly material that is not readily available.